考虑锈蚀影响的拉索状态UL列式分析法

针对拉索在服役期间经常出现的钢丝锈蚀及索力松弛病害现象,通过求解拉索微分方程边值问题及讨论索的收敛迭代解,引入Lemaitre的疲劳损伤应变等价原理和几何损伤理论,提出了在工程中拉索的锈蚀程度可通过适当折减拉索材料的弹性模量来表征,在此基础上,建立了计入拉索锈蚀和索力松弛影响的拉索状态UL列式分析方法,并成功运用到实际工程的拉索状态分析中。研究和工程实践表明拉索的锈蚀和索力松弛在服役期间拉索结构状态分析中不容忽视。所提供的方法,考虑了拉索锈蚀及索力松弛病害影响,为大跨度斜拉桥服役期间拉索状态较为精确的非线性分析提供了重要依据。

UL Formulation Analysis for Corrosion Effect on Cable State

As those are typical cable characteristics that steel cables are susceptible to corrosion and tend to stress relaxation after long term service,it is essential to take those damage characteristics into account in structural analysis to obtain actual behavior of cable in service.By introducing Lemaitre's equivalent strain principle and geometrical damage theory,the corrosion mechanism of cable was described by rational discount of the modulus of elasticity.A UL formulation for cable state was formulated after solving the boundary problem with the governing differential equation of the servicing cable.It is shown that corrosion and stress relaxation effects should not be ignored in the determination of in service cable state to ensure safety of the existing cable structures.With the proposed method,cable corrosion as well as stress relaxation has been taken into consideration,which leads to good precision and can meet the engineering requirements,and it provides a reliable approach to analyze the geometric nonlinearity of cables of existing long-span cable-stayed bridges.